1. Field of the Invention
This invention relates to a method of and a device for contact-printing the image of a transmission type original on a printing plate material such as photosensitive plastic film, resin plate, metal plate or the like.
2. Description of the Prior Art
In contact-printing the image of a transmission type original on a printing plate material carrying thereon a photosensitive layer, the original is registered with the printing plate material located on a printing stage at a predetermined position and then a flexible transparent sheet is positioned over the original to sealingly cover the original and the plate material. Thereafter, the space under the transparent sheet is evacuated to bring the transparent sheet, the original and the plate material into close contact with each other and the three members are then exposed to light.
In the above processes, it is required that the original be precisely registered with the plate material as well as that these two members be kept in close contact with each other.
In the conventional method, the positioning of the original on the plate material must be carried out every time the plate material is changed even when a plurality of plates are made from a single original. This lowers the efficiency of the operation and makes it difficult to raise efficiency by automatically supplying the plate materials.